Light emitting device and display apparatus including the same

Patent metadata

Field	Value
Publication number	US-10615372-B2
Application number	US-201816230527-A
Country	US
Kind code	B2
Filing date	Dec 21, 2018
Priority date	Dec 22, 2017
Publication date	Apr 7, 2020
Grant date	Apr 7, 2020

Abstract

A light emitting device including a micro cavity having a phase modulation surface and a display apparatus including the light emitting device are provided. The light emitting device includes a reflective layer including a phase modulation surface; a first electrode disposed on the phase modulation surface of the reflective layer; a light emitting structure disposed on the first electrode; and a second electrode disposed on the light emitting structure. The phase modulation surface may include a plurality of nano scale patterns that are regularly or irregularly arranged. The reflective layer and the second electrode may constitute the micro cavity having a resonance wavelength of the light emitting device.

First claim

What is claimed is:

1. A light emitting device comprising:
a metal reflective layer comprising a phase modulation surface;
a first electrode disposed on the phase modulation surface of the metal reflective layer;
a second electrode disposed to oppose the first electrode; and
a light emitting structure disposed between the first electrode and the second electrode to form a micro cavity having a resonance wavelength,
wherein the phase modulation surface comprises a plurality of nano light resonance structures, the plurality of nano light resonance structures being column type magnetic resonators in which a magnetic field component of incident light resonates at a periphery of nano scale patterns, and
wherein the resonance wavelength of the micro cavity is determined according to a phase delay caused by the plurality of nano light resonance structures and an optical distance between the metal reflective layer and the second electrode.

2. The light emitting device of claim 1 ,
wherein the first electrode is a transparent electrode, and
wherein the second electrode is a transflective electrode that reflects a part of light and transmits another part of the light.

3. The light emitting device of claim 2 , wherein the second electrode comprises a reflective metal, and an entire thickness of the second electrode is about 10 nm to about 20 nm.

4. The light emitting device of claim 1 ,
wherein the first electrode is a transparent electrode,
wherein the second electrode is a reflective electrode, and
wherein the metal reflective layer has a transflective property so that the metal reflective layer reflects a part of light and transmits another part of the light.

5. The light emitting device of claim 1 , wherein the metal reflective layer comprises silver (Ag) or an alloy comprising silver (Ag).

6. The light emitting device of claim 1 , wherein the phase modulation surface comprises a plurality of patterns that are regularly or irregularly arranged.

7. The light emitting device of claim 6 , wherein a phase delay of reflected light caused by the phase modulation surface is greater than a phase delay by an effective optical distance determined by multiplying a height of the patterns by a refractive index of the patterns.

8. The light emitting device of claim 6 , wherein a part of the first electrode is filled in a concave area of the patterns of the phase modulation surface.

9. The light emitting device of claim 6 , further comprising:
a dielectric substance filled in a concave area of the patterns of the phase modulation surface.

10. The light emitting device of claim 6 , further comprising:
a dielectric layer disposed between the phase modulation surface and the first electrode,
wherein a part of the dielectric layer is filled in a concave area of the patterns of the phase modulation surface.

11. The light emitting device of claim 6 , wherein a diameter of each of the patterns of the phase modulation surface is about 50 nm to about 150 nm.

12. The light emitting device of claim 6 , wherein a height of each of the patterns of the phase modulation surface is 0 nm to about 150 nm.

13. The light emitting device of claim 6 , wherein a period of the patterns of the phase modulation surface is about 100 nm to about 300 nm.

14. The light emitting device of claim 6 , wherein when a resonance wavelength of the micro cavity is λ, a diameter of each of the patterns of the phase modulation surface, a height of each of the patterns, and a period of the patterns are selected such that an optical length of the micro cavity is equal to n×λ/2, wherein n is a natural number.

15. The light emitting device of claim 1 , wherein the light emitting structure comprises:
a hole injection layer disposed on the first electrode;
a hole transport layer disposed on the hole injection layer;
an organic emission layer disposed on the hole transport layer;
an electron transport layer disposed on the organic emission layer; and
an electron injection layer disposed on the electron transport layer.

16. A display apparatus comprising:
a first pixel configured to emit light of a first wavelength; and
a second pixel configured to emit light of a second wavelength different from the first wavelength,
wherein each of the first pixel and the second pixel comprises:
a metal reflective layer comprising a phase modulation surface;
a first electrode disposed on the phase modulation surface of the metal reflective layer;
a second electrode disposed to oppose the first electrode; and
a light emitting structure disposed between the first electrode and the second electrode to form a micro cavity having a resonance wavelength,

wherein the phase modulation surface comprises a plurality of nano light resonance structures, the plurality of nano light resonance structures being column type magnetic resonators in which a magnetic field component of incident light resonates at a periphery of nano scale patterns, and
wherein the resonance wavelength of the micro cavity being determined according to a phase delay caused by the plurality of nano light resonance structures and an optical distance between the metal reflective layer and the second electrode.

17. The display apparatus of claim 16 ,
wherein the first electrode is a transparent electrode, and
wherein the second electrode is a transflective electrode that reflects a part of light and transmits another part of the light.

18. The display apparatus of claim 17 , wherein the second electrode comprises a reflective metal, and an entire thickness of the second electrode is about 10 nm to about 20 nm.

19. The display apparatus of claim 16 ,
wherein the first electrode is a transparent electrode,
wherein the second electrode is a reflective electrode, and
wherein the metal reflective layer has a transflective property such that the metal reflective layer reflects a part of light and transmits another part of the light.

20. The display apparatus of claim 16 , wherein the metal reflective layer comprises silver (Ag) or an alloy comprising silver (Ag).

21. The display apparatus of claim 16 , wherein the phase modulation surface comprises a plurality of patterns that are regularly or irregularly arranged.

22. The display apparatus of claim 21 , wherein a diameter of each of the patterns of the phase modulation surface of the first pixel, a height of each of the patterns, and a period of the patterns are selected such that the resonance wavelength of the micro cavity of the first pixel corresponds to the first wavelength, and
wherein a diameter of each of the patterns of the phase modulation surface of the second pixel, a height of each of the patterns, and a period of the patterns are selected such that the resonance wavelength of the micro cavity of the second pixel corresponds to the second wavelength.

23. The display apparatus of claim 21 , wherein a part of the first electrode is filled in a concave area of the patterns of the phase modulation surface.

24. The display apparatus of claim 21 , wherein each of the first pixel and the second pixel comprises a dielectric substance filled in a concave area of the patterns of the phase modulation surface.

25. The display apparatus of claim 21 , wherein each of the first pixel and the second pixel comprise a dielectric layer disposed between the phase modulation surface and the first electrode,
wherein a part of the dielectric layer is fill

Assignees

• Samsung Electronics Co Ltd
• Univ Leland Stanford Junior

Inventors

• Joo Wonjae
• Brongersma Mark L
• Esfandyarpour Majid

Classifications

• H01L51/5218

  Electricity · mapped topic

• H01L51/5265 Primary

  Electricity · mapped topic

• H01L51/5072

  Electricity · mapped topic

• H01L51/5206

  Electricity · mapped topic

• H01L27/3211

  Electricity · mapped topic